Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10529278 | Analytica Chimica Acta | 2005 | 8 Pages |
Abstract
Microwave-assisted extraction (MAE) of nonylphenols (NP), nonylphenol mono- and diethoxylates (NP1EO and NP2EO, respectively) and phthalate esters was optimised using an experimental design approach. A D-optimal mixture design was used to optimise the pressure inside the extraction vessel (110-207Â kPa), the extraction time (5-25Â min) and the extraction solvent (methanol, acetone or n-hexane) or the solvent mixture for the microwave-assisted extraction. Percentage of microwave power (80%) and solvent volume (15Â ml) were fixed in all the experiments. As a consequence, the optimum extraction of these compounds was carried out at an intermediate pressure (159Â kPa) with pure methanol and during 15Â min. Moreover, solid phase extraction was also optimised for the clean-up of the extracts and C-18, LiChrolut® and Oasis® cartridges were studied in order to obtain the best recoveries of the compounds of interest. The highest recoveries were obtained with LiChrolut® cartridges after the elution with ethyl acetate. The cleaned extracts were analysed in a gas chromatograph with mass spectrometric detection and in a liquid chromatograph with diode array and fluorescence detection (HPLC-DAD-UV-FLD). The same sediment was also extracted twice in order to check that an exhaustive extraction of the analytes had occurred. Finally, the optimised extraction method was compared with pressurised solvent extraction (PSE), using an estuarine sediment sample.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
E. Cortazar, L. Bartolomé, A. Delgado, N. Etxebarria, L.A. Fernández, A. Usobiaga, O. Zuloaga,